Ten 22 year old radiata pine trees growing in two stands in Chile, one in clay and the other in humid sand soils showing some lean, were assessed for chemical composition and wood density of compression wood. Significant differences in type of wood in density (33 kg/m³), lignin (1.944 %), alpha-cellulose (-2.634 %), ethanol toluene extractives (0.567 %) and pentose (0.742 %) were found between matched sample of compression and opposite woods. Differences in juvenile and mature wood were significant for both density (-4 kg/m³) and pentose (1.628 %), and site differences were found for wood density (28 kg/m³), extractives (0.978 %) and apparent for alpha cellulose (1.223%). In comparison with other studies, our results suggested that the compression wood formed from trees with light visible lean corresponded to a mild compression class.